1. Technical Field of the Invention
This invention relates to industrial forklift trucks. More particularly, and not by way of limitation, the invention is directed to a forklift safety sensor and control system for preventing unsafe wear on the tines of the fork.
2. Description of Related Art
After setting down a load, forklift drivers often back up and then drive a considerable distance with the bottom surface of the tines of the fork contacting the ground. This causes excessive wear of the tines. Over a period of time, the tines are ground down until the thickness of the tines becomes a safety problem. The forklift may be rated to lift loads of a particular weight, but the thickness of the tines of the fork have been ground down to the point that they are not capable of holding the weight to which the forklift has been rated. The area where the fork makes a right angle from the vertical to the horizontal is referred to as the “heel” of the fork. The heel is a critical area for the load-carrying capacity of the fork. As little as a ten percent loss of metal through wear on the bottom surface of the heel reduces the lifting capacity of the fork by twenty percent. Severe injury and property damage may result if one or both of the tines fails under a heavy load.
OSHA has restrictions and guidelines regarding excessive wear on the tines of forklift forks (see ASME/ANSI B56.1D-1993). The thickness of the tines may be measured utilizing fork calipers specially designed for this function. Often, however, because of the expense of the forks, operators of forklifts may not replace the forks, even when the measured thickness of the tines is less than the OSHA guidelines. Thus, the current efforts to prevent this unsafe condition are not effective.